19786421 has 4 divisors (see below), whose sum is σ = 19801344. Its totient is φ = 19771500.

The previous prime is 19786411. The next prime is 19786423. The reversal of 19786421 is 12468791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19786421 - 2²² = 15592117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19786423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5255 + ... + 8196.

It is an arithmetic number, because the mean of its divisors is an integer number (4950336).

Almost surely, 2^19786421 is an apocalyptic number.

It is an amenable number.

19786421 is a deficient number, since it is larger than the sum of its proper divisors (14923).

19786421 is a wasteful number, since it uses less digits than its factorization.

19786421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14922.

The product of its digits is 24192, while the sum is 38.

The square root of 19786421 is about 4448.1930039062. The cubic root of 19786421 is about 270.4720639728.

The spelling of 19786421 in words is "nineteen million, seven hundred eighty-six thousand, four hundred twenty-one".